Although there theoretically are many ways to improve the hydrophilic properties (hydrophilicity) of a pigment, many require either expensive components or expensive equipment to achieve the desired goal. Often, the use of a high power grinding process is still required to make the pigment particle size small enough.
Accordingly, a need exists for pigments with good hydrophilic properties and that have one or more of the following properties: (1) exhibit a small particle size distribution, (2) have good dispersibility in highly polar solvents, such as water, (3) require little or no grinding energy, (4) have good chemical resistance and good color strength, and (5) can be manufactured in an environmentally safe manner. A method to make such pigments is required.
It has been suggested that one means of increasing the hydrophilic properties of pigments would be to introduce ionic moieties on the surface of the pigment particles, as by coating the surface of the pigment with an ionomer. The means to accomplish such a modification, to date, however has been elusive, with complex, expensive approaches being used. A specific need, therefore, has existed for a means to modify pigment surfaces with an ionomer effectively, while using an environmentally safe and simple process.